Electric furnace and process of heating substances uniformly and at a controllable temperature.



' j esses of lleatinfg Substances Uniformly and' llhlllTE nuten.

ERWIN F. VON WKLMOWSKY, DECEASED, LATE OF BOSTON, MASSACHUSETTS, BY EEWIN J. PRINDLE, `EXEITLOIEE., 0F EAST ORANGE, NEW" JERSEY, ASSIGNOR T0 MRS. OLG-A.

PIEPER, or rofrsnelvr, 'GERMANY ELECTRIC FUR-NACE AND PROCESS OF HEATING SUBSTANCES UNIFORMLY ANDV AT A CONTROLLABLE TEMPERATURE.

Loo-asas.

Specification of Letters Patent.

Patented Apr. 21, 1911i.,

originar applicati@ area catcher as, 189e, serial no. 610,286. Divided and this application ated January Y f 17,1914. serialNo. 512,801.

To all whom 'it m oy formera Be it known.thatEnwrN F. voN Murrowsnr, deceased, late acitizcn of the United States. of America.and-resident of Boston, count)v of Suffolk, Commonwealth of Massa'- chuselts, did invent'cert-ain new and useful Improvements in Electric Furnaces and Procat a VCont-reliable Temperature, of'whic'h the following is a specification. Y

The hpresent applicationv is. a division of original application'Serial No. 6l0,286, tiled October '28, 1896, and includes subject matter erased without prejudice from said original application with the express intention of applyingl for a separate patent.

This invention relates in general to the treatment. of substances electrically, and more particularly to the treatment of gases.

The inventor hasivfound that an arc-furnace in which the materials to be heated' are brought directly into the arc and exposed to its inliuence, has the disadvantage that where the arc happens to pass the contents are overlieated and, if in a solid or liquid state, partly volatilized 'or scattered around, while the particles close by are heated insuihciently or too slowly. i i

Now, the object of the invention is to heat substances uniformly in an electric arc, at a `controllable and `(Where desirable) at a reduced temperature, and to make the operation continuous. This is accomplished by the means and processes hereinafter described.

The invention' consists therefore inthe novel ymeans and Aprocess hereinafter set forth and illustrated in the drawings.

' Apparatus for carrying the process into effect is illustrated in the accompanying drawings, and this, as well as the process which is thereby carried out, l'will be described hereinafter.

In the drawings, Figure 1 is a central longitudinal section of a furnace and its electrical and mechanical connections and accessories; Fig. 2 is a diagrammatic view of a modification thereof, certain of the elec trical and mechanical connections heilig omitted. 1- f 'j Referring to the drawings, A', A2, Aa and A4 are tubes of conducting, non-,magnetic or only slightly Imagnetic material chosen to orI made to'resista high temperature, preferably carbon with a few per cent..of carbids 1n it, such as is used for electrolytic work.

o2, a3, are radially arranged hollow carbon rods cemented into the respective tubes A', A2, A3 and A* by graphite cement andrserving to conduct the electric current to said tubes, each of which is one of'a pair of electrodes, but serving alsoas means of currentsupply and as guides for carbon pencils or solid carbon rods a3 closely fittinginto said hollow rods a2. Such a pencil can be moved forward and backward and serves to strike an are in starting the furnace.

B is a central electrode extending within l and through the tube electrodes A', A2', A3 and A4, between which :tube electrodes and central electrode the arc is' struck by pencils a3.

a4 is a shell of fire-bricks or loose magnesia, outside of which is an external iron cas-l ing a5.

c is a solenoid surrounding the reaction chamber within the furnace and is separated from the external casing a5 by an asbestos layer o6. The solenoid c, when continuous or single-phase alternating currents are used, is connected in series with the arc-current and in parallel with a rheostat, so that the magnetism may be regulated independently of the arc-current. When two-phase cur rents are used, one phase for the are and the other phase for-the solenoid, .the rheostatis put in serieswith the solenoid. The former of these arrangements of circuits is illustrated in Fig. l, where Vg represents a separately excited generator of either the direct current or single-phase alternating type, and i the rhepstat.'

The reaction chamber of the furnace is provided with a conduit d of refractory material for the gases to be treated, and a closed circuit of this conduit is completed by pipe d. In a part of this circuit, such as pipe d', is provided a fan Z2 of refractory material with lcooled axle. hearings and driven from the outside. Through one of two openings, d3, dt, provided in the inclo- Vsure of said circuit, new gas or vapor is added in continuous stream, while through the cuit a corresponding volume of gases or between these rods and the lower end of.v

rod B, and then an arc is established by withdrawing the rods f cylinder A?, as

described'more fully in an application for Letters Patentconcerning the regulation of the position ofan arc-disk, which application was filed-Oct. 28,1896, Serial `Number 610,985. Thereupon by withdrawing the rods of cylinder Aa and severing said connection of these rods.-with the lower end of rod B, another arc is'established at the level of the rods of cylinder A3, while the pres- 'sure of the dynamo isincreased at the same t-ime by more than fty volts, according tov the distance between the central rod B and the tubes or cylinders. These arcs will be extinguished `repeatedly until the temperature is high. lIn this way a series of disks is gradually established between concentric cylindrical surfaces, through which disks thev charge is moved. The disks can be formed ,accordingto the desired temperature offs. vastly different current-density. If they' are .intended to be of very low temperature comparatively, and the central carbon 'rod off-a. furnace intended vfor gases has'fe.', ,g. one-half inch diameter, the carbon tube inside one and one-half (1%) inches diameter, ythe area between the rod andv the tube .being therefore one and sixtenths( 1.6)vr sq.7inches, then an energy supply of 'aboutufifteen (15) amperes and fortyfivez"(45')l volts'continuous current in a magneticfield of 15() ampere-turns will give a1- ready a perfect luminous disk, while with alternating current about sixty (60) volts and fifty-five (55) amperes are needed, with 400 ampere-turns for the solenoid. These gures depend uponthe preparation of the carbon and above all upon the temperature existing already in the furnace. .To reduce the temperature of the disk as far as possible, first the solenoid-current is reduced, then the-volts. vvTo do this conveniently dynamos with separately excited elds are used.

A 'modified and similar arrangement for the treatment'of gases is shown diagrammatically in. Fig.v 2, the details of construction being 'omitted but these may be the same as shownfin-Fig. 1 or in the original application hereinbeforef referred to, as far as applicable. In this figure A is an insulatedtube, and B', B2, Bs are parts of the central electrode. This furnace can be started without carbon rods by moving B8- toward'l B? until it touches, and withdrawing and producing an arc at first between Ba and'B. Thereafter when the electrodedistance increases and the current,v at last.

prefers to use the .insulated outside tube A as part ofits way, twodisks are formed-'- between Bajand the tube, and between the' tube and Andiat last two or' more disks are established in the same way by moving B', between B and the tube and between 'A the tube and B2. It is clear 'from what has been said, how to arrange for a larger numberof disks, when suchlarger number is desired. 4

" In the operation of these furnaces, after the arc has been started, the effect of the solenoid is rstto cause the arc to rotate. Should the'arc be extinguished, the solenoid current is weakened and the arc again started. 'As'soonas the furnace has reached a high temperature," amore or less regularly rotating arcis' seenjgc'.y e. a luminous, more 4lor less spiral broad line, or-lines, be-

tween'some rotating, brightly incandescent spots on the electrodes. This rotating arc avoids overheating to va'oerta-in extent, lbut is for most purposes not va/ sutlicient solution of the problem mentioned in the preambie. The magnetism, and atthe same time the voltage of the main current, are now increased until the rotating arel is transformed into a homogeneous luminous disk, hereinbefore referred to as the arc-disk or th,ef-`disk. Thereby the highest temperature existing in the furnace' is reduced considerably, though the supply of energy is increased,.the heat being now uniform. The electric fdischarge in this -form isperrfectly-v steady' and controllable, A homogeneous lu'mmous disk stretghesitself across -the tube, making on the two'l electrodes rings oftentirely uniform and moderate brightness. No 'rotation whatever is visible, and

the electricity appears to stream simnltaneously between said ringsanotpreferrmg at any one moment a special lmear path.

vThis disk, when only a fewv inches 1n d1- ameter, is noiseless, except with alternating current, which besides requires, in order to forma disk, more amperes and more volts for the same apparatus., When the disk is once formed, any increase in current will increase the luminosity and t-he temperature, which latter can be regulated with precision by regulating the current-supply. When the central electrode is moved even considerably out of its central position the disk is not changed thereby in its appearance or uniform luminosity, and no motion in it is visible. kWhen the magnetism is sustained and the current for the disk reduced, the disk is changed at last into a quick rotating arc omitting a roaring noise,

even if less thanV two inches l,in diameter,

This is another striking difference-between theA disk'and the rotating arc.

The simultaneous-streaming of electricity mentioned above makes this furnace particuabove mentioned for treatment of solid inaipa/asta lai-ly fitto Ipass therethrough gases 'or vapors which are to be exposed to electrolytic and electro-synthetic forces or to be heated toa certain temperature favorable to a desired reaction. 'The feedin tube may be located adjacent the outlet tu e so that the heat from the outcoming stream of gases is communicated tothe fresh gas mixture.

This may be done by dividing the feeding tube e shown in'v theA original application terials, this ltube-being stationary instead of rotating.

following claims, the Word narc- .its character and appearance may be.

Claims: i l n Y l. The' process which consists in estabiishing an electric arc, creating a magnetic eld adapted to disperse or spread said arc and passing a currcnto gas or gases past in contact with said arc.

2... The process which consists in estabiisbing an electric arc in a magnetic tield and transverse to thejfiux of the saine and pass` ing a current of gas to be treated past said arc and in contact With the same.

gas to be treated pastsaid arc and in contactl with the same.

, a. Thacombinati'on, with means for proy 3. The lprocess which consists in estalciish-` ducing avmagnetic ieldrof means vorproducing an electric arc in said field, and means for assinocurrent of Gas into contact Y o b With and past said electric arc.

5. The combination, with means for producing amagnetic field, of electrodes lo- Y cated in said'ield, means for supplying electricity to Asaid electrodes, and means for passing a current of gas past said electrodes.

6. The combination, vvithxiieans for producing a magnetic-field of .means for 'pro- .ducing an arc'trans'verselyte the flux' of said magnetic field andimeans for supplying a gas to said arc i I 7 in an electric furnace for treating gases by means of voltaic arcsthe combination, of

a furnace chamber, r,an inner central elecF trede, anouter electrode concentric therewith, means around the furnace for creating a magnetic iield in the space Within the said outer electrode, and means for moving gases through the said furnace chamber, substantially as and for the purpose set forth.

Safin apparatus for producing" chemical reactions in a mass of gases, consisting of means-tor forming an electric arc and causing the latter to play in the mass of gases, the said arc being subjected to. the action of a magnetic ield produced by a stationary Asource or magnetism, the said magnetic field causing the arc to rotate in one plane abdut the airis of one of the electrodes. i f EDWN J. PRINDLE, Emeric/,tor of tite estate 0 f Emoz'fn F. con, Wz'lwwwsky.

l Titnesses: v

' VIOLET G. LLOYD,

- L. BRODERIGK. 

